Punching presses include punching heads to which punching tools are able to be mounted and dismounted. Punching tools that are constructed as punching dies have a cylindrical tool shaft and a plate-like adjustment ring that extends in a radial direction of the tool shaft. In order to receive the tool shaft, a tool receiving member is provided on the punching head. When a punching die is mounted, the punching head and the relevant punching tool are positioned relative to each other in such a manner that the tool shaft of the punching die comes to rest inside of the tool receiving member of the punching head. In such an instance, the tool shaft of the punching die moves between the collet members of a collet chuck located inside of the punching head. Such a configuration is part of an axial tensioning device and is fitted as such to a piston rod of a piston/cylinder unit of the axial tensioning device.
The piston rod of the piston/cylinder unit is coaxial with the tool shaft of the punching die. If the piston rod is pulled back in an axial direction by appropriate application of a pressure to the piston/cylinder unit, the collet chuck fitted to the piston rod closes, and the collet members of the collet chuck acting as axial tensioning elements engage with the free ends thereof behind a shaft step that is formed on the tool shaft of the punching die. With continued retracting movement of the piston rod, the tool shaft of the punching die is drawn by the collet chuck towards the interior of the tool receiving member until the adjustment ring that protrudes laterally over the tool shaft of the punching die moves into abutment with the edge of the tool receiving member, and the punching die is ultimately pulled by the adjustment ring against the edge of the tool receiving member in an axial direction of the tool shaft.